Protein extraction from Atriplex lampa leaves: Potential use as forage for animals used for human diets

The purpose of this study was to evaluate the effectof pH on the extraction of protein nitrogen from Atriplex lampa leaves (Moquin) Dietrich. Thechemical characterization of the dry matter indicated thefollowing (g/100 g): protein, 26.93; ash, 21.80; etherextract, 4.65; dry matter, 37.30; sodium, 6.05; and calcium, 0.41.Non-critical values were obtained for saponins andnitrates. The high concentration of oxalic acid (8.52 g/100 g),together with elevated salt content accountfor the low palatability of the studied species.In order to determine the parameters needed to improvethe extraction in protein nitrogen from leaves, freshmaterial was macerated with 2% sodium metasulfite,followed by pulping with a hand-driven grinder.Extractions were performed at different pH values(2–12) adjusting the value with 5N HCL or NaOH, withagitation followed by centrifugation and pressing.Supernatants were collected and kept. The lastextraction was performed with Tween 20 in order toobtain maximum nitrogen recovery from the residuecake. Highest extraction (41.23%) was obtained at pH10 with a 1:5 ratio (leaf : deionized water, w/v). Itis proposed that this regional natural resource may beused to elaborate a protein concentrate, which can bemade more palatable by decreasing potassium and sodiumsalt content with the use of membrane technology.